Probes with printed tips are desirable for probing signals carried by a transmission line on a target board and transferring them to an oscilloscope for analysis. Measuring electrical signals carried by a transmission line on a target printed circuit board to determine their electrical characteristics is an important part of validating or troubleshooting a circuit performance. Signal measurement and analysis can also be useful in a service and repair environment to diagnose malfunctions.
Demand for higher data transfer rates and signal frequencies have created a need for printed circuit boards to transmit signals at ever-increasing frequencies with the accompanying need for probes that can faithfully replicate these rates and frequencies without disturbing the target signal. At high frequencies, such as microwave frequencies, existing probes have three undesirable features:
1. Capacitive loading of the transmission line being measured because of the proximity of the probe material. This disrupts the impedance of the line at the point being measured and causes reflections.
2. Inductive intervention of the probe because of the length of its probe tip. This inductance in series with the probe tip limits the bandwidth of the probe.
3. The basic shunt impedance of the probe itself.
The use of edge contacts on probes is known in the prior art. For example, edge printing has been used on hybrids to create wraparound connections, and crenellation vias have been used on printed circuit boards. However, these contacts are used to push up against an intervening material used to probe, which is usually an elastomeric material. Other implementations of an edge print form the probe tip through the addition of a soldered or epoxied wire.
Therefore, a need exists for a new and improved probe with printed tip that can be used for probing signals carried by a transmission line on a target board directly without the need for an extra mechanical extension and transferring them to an oscilloscope for analysis. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the probe with printed tip according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of probing broadband microwave signals carried by a transmission line on a target board without circuit disruption and then routing them with high fidelity to an oscilloscope for analysis.